/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.util;

import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.lang.Thread.UncaughtExceptionHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.hadoop.util.ReflectionUtils;
import org.apache.hadoop.util.StringUtils;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;

/**
 * Thread Utility
 */
@InterfaceAudience.Private
public class Threads {
    private static final Logger LOG = LoggerFactory.getLogger(Threads.class);
    private static final AtomicInteger poolNumber = new AtomicInteger(1);

    public static final UncaughtExceptionHandler LOGGING_EXCEPTION_HANDLER = new UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
            LOG.warn("Thread:" + t + " exited with Exception:" + StringUtils.stringifyException(e));
        }
    };

    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to run
     * @return Returns the passed Thread <code>t</code>.
     */
    public static <T extends Thread> T setDaemonThreadRunning(T t) {
        return setDaemonThreadRunning(t, t.getName());
    }

    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to frob
     * @param name new name
     * @return Returns the passed Thread <code>t</code>.
     */
    public static <T extends Thread> T setDaemonThreadRunning(T t, String name) {

        /********
         * TODO_MA 马中华 https://blog.csdn.net/zhongqi2513
         *   注释：
         */
        return setDaemonThreadRunning(t, name, null);
    }

    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to frob
     * @param name new name
     * @param handler A handler to set on the thread. Pass null if want to use default handler.
     * @return Returns the passed Thread <code>t</code>.
     */
    public static <T extends Thread> T setDaemonThreadRunning(T t, String name, UncaughtExceptionHandler handler) {
        t.setName(name);
        if(handler != null) {
            t.setUncaughtExceptionHandler(handler);
        }

        /********
         * TODO_MA 马中华 https://blog.csdn.net/zhongqi2513
         *   注释： 启动参数线程
         */
        t.setDaemon(true);
        t.start();
        return t;
    }

    /**
     * Shutdown passed thread using isAlive and join.
     * @param t Thread to shutdown
     */
    public static void shutdown(final Thread t) {
        shutdown(t, 0);
    }

    /**
     * Shutdown passed thread using isAlive and join.
     * @param joinwait Pass 0 if we're to wait forever.
     * @param t Thread to shutdown
     */
    public static void shutdown(final Thread t, final long joinwait) {
        if(t == null)
            return;
        while(t.isAlive()) {
            try {
                t.join(joinwait);
            } catch(InterruptedException e) {
                LOG.warn(t.getName() + "; joinwait=" + joinwait, e);
            }
        }
    }


    /**
     * @param t Waits on the passed thread to die dumping a threaddump every
     * minute while its up.
     * @throws InterruptedException
     */
    public static void threadDumpingIsAlive(final Thread t) throws InterruptedException {
        if(t == null) {
            return;
        }

        while(t.isAlive()) {
            t.join(60 * 1000);
            if(t.isAlive()) {
                printThreadInfo(System.out, "Automatic Stack Trace every 60 seconds waiting on " + t.getName());
            }
        }
    }

    /**
     * If interrupted, just prints out the interrupt on STDOUT, resets interrupt and returns
     * @param millis How long to sleep for in milliseconds.
     */
    public static void sleep(long millis) {
        try {
            Thread.sleep(millis);
        } catch(InterruptedException e) {
            LOG.warn("sleep interrupted", e);
            Thread.currentThread().interrupt();
        }
    }

    /**
     * Sleeps for the given amount of time even if interrupted. Preserves
     * the interrupt status.
     * @param msToWait the amount of time to sleep in milliseconds
     */
    public static void sleepWithoutInterrupt(final long msToWait) {
        long timeMillis = System.currentTimeMillis();
        long endTime = timeMillis + msToWait;
        boolean interrupted = false;
        while(timeMillis < endTime) {
            try {
                Thread.sleep(endTime - timeMillis);
            } catch(InterruptedException ex) {
                interrupted = true;
            }
            timeMillis = System.currentTimeMillis();
        }

        if(interrupted) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * Create a new CachedThreadPool with a bounded number as the maximum
     * thread size in the pool.
     *
     * @param maxCachedThread the maximum thread could be created in the pool
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument
     * @param threadFactory the factory to use when creating new threads
     * @return threadPoolExecutor the cachedThreadPool with a bounded number
     * as the maximum thread size in the pool.
     */
    public static ThreadPoolExecutor getBoundedCachedThreadPool(int maxCachedThread, long timeout, TimeUnit unit, ThreadFactory threadFactory) {
        ThreadPoolExecutor boundedCachedThreadPool = new ThreadPoolExecutor(maxCachedThread, maxCachedThread, timeout, unit,
                new LinkedBlockingQueue<>(), threadFactory);
        // allow the core pool threads timeout and terminate
        boundedCachedThreadPool.allowCoreThreadTimeOut(true);
        return boundedCachedThreadPool;
    }


    /**
     * Returns a {@link java.util.concurrent.ThreadFactory} that names each created thread uniquely,
     * with a common prefix.
     * @param prefix The prefix of every created Thread's name
     * @return a {@link java.util.concurrent.ThreadFactory} that names threads
     */
    private static ThreadFactory getNamedThreadFactory(final String prefix) {
        SecurityManager s = System.getSecurityManager();
        final ThreadGroup threadGroup = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();

        return new ThreadFactory() {
            final AtomicInteger threadNumber = new AtomicInteger(1);
            private final int poolNumber = Threads.poolNumber.getAndIncrement();
            final ThreadGroup group = threadGroup;

            @Override
            public Thread newThread(Runnable r) {
                final String name = prefix + "-pool" + poolNumber + "-t" + threadNumber.getAndIncrement();
                return new Thread(group, r, name);
            }
        };
    }

    /**
     * Same as {#newDaemonThreadFactory(String, UncaughtExceptionHandler)},
     * without setting the exception handler.
     */
    public static ThreadFactory newDaemonThreadFactory(final String prefix) {
        return newDaemonThreadFactory(prefix, null);
    }

    /**
     * Get a named {@link ThreadFactory} that just builds daemon threads.
     * @param prefix name prefix for all threads created from the factory
     * @param handler unhandles exception handler to set for all threads
     * @return a thread factory that creates named, daemon threads with
     *         the supplied exception handler and normal priority
     */
    public static ThreadFactory newDaemonThreadFactory(final String prefix, final UncaughtExceptionHandler handler) {
        final ThreadFactory namedFactory = getNamedThreadFactory(prefix);
        return new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread t = namedFactory.newThread(r);
                if(handler != null) {
                    t.setUncaughtExceptionHandler(handler);
                } else {
                    t.setUncaughtExceptionHandler(LOGGING_EXCEPTION_HANDLER);
                }
                if(!t.isDaemon()) {
                    t.setDaemon(true);
                }
                if(t.getPriority() != Thread.NORM_PRIORITY) {
                    t.setPriority(Thread.NORM_PRIORITY);
                }
                return t;
            }

        };
    }

    /** Sets an UncaughtExceptionHandler for the thread which logs the
     * Exception stack if the thread dies.
     */
    public static void setLoggingUncaughtExceptionHandler(Thread t) {
        t.setUncaughtExceptionHandler(LOGGING_EXCEPTION_HANDLER);
    }

    private static interface PrintThreadInfoHelper {

        void printThreadInfo(PrintStream stream, String title);

    }

    private static class PrintThreadInfoLazyHolder {

        public static final PrintThreadInfoHelper HELPER = initHelper();

        private static PrintThreadInfoHelper initHelper() {
            Method method = null;
            try {
                // Hadoop 2.7+ declares printThreadInfo(PrintStream, String)
                method = ReflectionUtils.class.getMethod("printThreadInfo", PrintStream.class, String.class);
                method.setAccessible(true);
                final Method hadoop27Method = method;
                return new PrintThreadInfoHelper() {

                    @Override
                    public void printThreadInfo(PrintStream stream, String title) {
                        try {
                            hadoop27Method.invoke(null, stream, title);
                        } catch(IllegalAccessException | IllegalArgumentException e) {
                            throw new RuntimeException(e);
                        } catch(InvocationTargetException e) {
                            throw new RuntimeException(e.getCause());
                        }
                    }
                };
            } catch(NoSuchMethodException e) {
                LOG.info("Can not find hadoop 2.7+ printThreadInfo method, try hadoop hadoop 2.6 and earlier", e);
            }
            try {
                // Hadoop 2.6 and earlier declares printThreadInfo(PrintWriter, String)
                method = ReflectionUtils.class.getMethod("printThreadInfo", PrintWriter.class, String.class);
                method.setAccessible(true);
                final Method hadoop26Method = method;
                return new PrintThreadInfoHelper() {

                    @Override
                    public void printThreadInfo(PrintStream stream, String title) {
                        try {
                            hadoop26Method.invoke(null, new PrintWriter(new OutputStreamWriter(stream, StandardCharsets.UTF_8)), title);
                        } catch(IllegalAccessException | IllegalArgumentException e) {
                            throw new RuntimeException(e);
                        } catch(InvocationTargetException e) {
                            throw new RuntimeException(e.getCause());
                        }
                    }
                };
            } catch(NoSuchMethodException e) {
                LOG.warn("Cannot find printThreadInfo method. Check hadoop jars linked", e);
            }
            return null;
        }
    }

    /**
     * Print all of the thread's information and stack traces. Wrapper around Hadoop's method.
     *
     * @param stream the stream to
     * @param title a string title for the stack trace
     */
    public static void printThreadInfo(PrintStream stream, String title) {
        Preconditions.checkNotNull(PrintThreadInfoLazyHolder.HELPER, "Cannot find method. Check hadoop jars linked").printThreadInfo(stream, title);
    }
}
